Patient support formed from an elastomeric composition including a polymer blend of seeps copolymers

ABSTRACT

This disclosure provides a person support formed from an elastomeric composition. The elastomeric composition includes a polymer blend with the polymer blend consisting essentially of a first and second SEEPS copolymer. The first and second SEEPS copolymers are present in the polymer blend in an amount of from 75 to 95 percent by weight and 5 to 25 percent by weight, respectively, based on the total weight of the polymer blend. In addition, the sum of the first and second SEEPS copolymers in the polymer blend is 100 percent by weight. The first and second SEEPS copolymers have a weight average molecular weight of weight of at least 200,000 and 125,000 to 175,000, respectively. The disclosure also provides a patient support for supporting a patient with the patient support formed from the elastomeric composition.

CROSS-REFERENCE TO RELATED APPLICATION

The subject patent application claims priority to and all the benefitsof U.S. Provisional Patent Application No. 62/777,911 filed on Dec. 11,2018, the disclosure of which is hereby incorporated by reference in itsentirety.

BACKGROUND

Many patient supports (e.g., mattresses) are designed to minimizepressure on the body, yet remain inadequate. Ideally, a patient supportshould provide a nearly uniform pressure plateau over a wide range ofdisplacements that result from patients of varying body weights usingthe patient support. Instead, many patient supports tend to have anextended elastic response (for lighter weight patients) or densificationand bottoming out of the patient support (for heavier weight patients).Both scenarios are undesirable.

A patient support having a new and improved formulation designed toaddress one or more of the aforementioned deficiencies is desired.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the present disclosure will be readily appreciated as thesame becomes better understood by reference to the following detaileddescription when considered in connection with the accompanyingdrawings.

FIG. 1 is an elevational view of a patient support apparatus including apatient support.

FIG. 2 is an exploded view illustrating a crib assembly, spacer layer,and a cover assembly.

FIG. 3 is a perspective view of the crib assembly and the spacer layer.

FIG. 4 is a cross-sectional view of the crib assembly and the spacerlayer.

FIG. 5 is an exploded view of the crib assembly and the spacer layer.

FIG. 6 is an exploded view of a bottom cover assembly.

FIG. 7 is a perspective view of the crib assembly illustrating latticesof cells for supporting a patient.

FIG. 8 is an exploded and perspective view of a lattice of cellsillustrating coupling features used to connect the lattice of cells to acrib of the crib assembly.

FIG. 9 is a top view of the lattice of cells from FIG. 8 .

FIG. 10 is a perspective view of a cell formed as a hexagonal shapedcolumn.

FIG. 11 is a graph comparing average droop for test plaques ofelastomeric compositions having varying ratios of a first and secondSEEPS copolymer.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure provides a patient support formed from anelastomeric composition. As described in detail below, the elastomericcomposition is useful for forming cells used in a lattice of cells ofthe patient support. It should be appreciated, however, that theelastomeric composition is also useful for providing other types ofsupports, including, supports for persons in non-medical settings (e.g.,personal mattresses, automotive seating, furniture, and the like).

The elastomeric composition includes a polymer blend of SEEPS(styrene-[ethylene/ethylene-propylene]-styrene) copolymers. SEEPScopolymers are block copolymers that exhibit rubber-like properties overa broad temperature range. In particular, SEEPS copolymers are formed asthe reaction product from a hydrogenated styrene isoprene/butadieneblock copolymer or, more particularly, are made from hydrogenatedstyrene block polymers as endblocks with 2-methyl-1,3-butadiene and1,3-butadiene below according to formula (I) below:

The SEEPS copolymers described herein include relative amounts of theharder styrenic blocks (corresponding to the amounts of subscripts 1 andn present in formula (I)) and softer diene blocks (corresponding to theamount of subscript m in formula (I), which is further differentiated bythe relative amounts of 2-methyl-1,3-butadiene (i.e., polyisoprene) and1,3-butadiene according to subscripts k and 1).

In certain embodiments, the polymer blend consists essentially of ablend of two SEEPS copolymers, both copolymers in accordance withformula (I) above, but having differing weight average molecular weightsas measured via gel permeation chromatography. In further embodiments,the polymer blend consists of a blend of two SEEPS copolymers, bothcopolymers in accordance with formula (I) above, but having differingweight average molecular weights as measured in grams per mole via gelpermeation chromatography. In certain embodiments, the two SEEPScopolymers have an average molecular weight difference of at least10,000, such as at least 25,000, such as from 75,000 to 200,000.

The first SEEPS copolymer is a high molecular weight SEEPS copolymerhaving a weight average molecular weight of greater than 200,000; suchas from 200,000 to 325,000; such as from 295,000 to 315,000; or such asabout 308,000, as measured by gel permeation chromatography. In certainembodiments, in addition to the weight average molecular weight range,this first SEEPS copolymer has a styrenic content of about 30%.

The second SEEPS copolymer is a medium molecular weight SEEPS copolymerhaving a weight average molecular weight of from 125,000 to 175,000,such as about 150,000, as measured by gel permeation chromatography. Incertain embodiments, in addition to the weight average molecular weightrange, this second SEEPS copolymer has a styrenic content of about 32%.

In particular, the polymer blend consists essentially of, oralternatively consists of, from 75 to 95 weight percent of the firstSEEPS copolymer (i.e., 75 to 95% by weight of the first SEEPScopolymer), and from 5 to 25 weight percent of the second SEEPScopolymer (i.e., from 5 to 25% by weight of the second SEEPS copolymer),for a sum total of 100 weight percent, based on the total weight of thepolymer blend. In further embodiments, the polymer blend consistsessentially of, or consists of, 85 weight percent of the first SEEPScopolymer, and 15 weight percent of the second SEEPS copolymer, for asum total of 100 weight percent.

The term “about”, as it relates to the further description of molecularweight, is intended to refer to values that are within 5,000 of thestated value. Accordingly, a weight average molecular weight of “about150,000” includes SEEPS copolymers having a weight average molecularweight between 145,000 and 155,000. As another example, a weight averagemolecular weight of “about 308,000” includes SEEPS copolymers having aweight average molecular weights between 303,000 and 313,000. Withrespect to styrenic content, the term “about” is intended to refer tovalues that are within 2 units of their stated values. Accordingly, thefirst SEEPS copolymer having a stated styrenic content of about 30% mayvary between 28% and 32%, and the second SEEPS copolymer having a statedstyrenic content of about 32% may vary between 30% and 34%.

The term “polymer blend”, as defined herein with respect to theelastomeric composition, refers to all of the SEEPS copolymers presentin the elastomeric composition. In certain embodiments, the “polymerblend” is the first and second SEEPS polymers as described above, anddoes not include additional SEEPS polymers. The polymer blend does notrefer to other components of the elastomeric composition, includingother polymers that are different from SEEPS and that may be present inthe elastomeric composition such as mineral oil, described below.Although not required, typically the elastomeric composition does notinclude polymers other than the polymers present in the polymer blend.In other words, typically, the only polymers present in the elastomericcomposition are included in the polymer blend with the polymer blendconsisting of the first and second SEEPS copolymers.

Referring still to the elastomeric composition, the elastomericcomposition may also include an extender, e.g. mineral oil, which iscombined with the polymer blend to provide a desired combination of meltviscosity and processing temperatures for the elastomeric compositionwhen forming the patient support. The polymer blend of SEEPS hassufficient hydrogenation to provide Van der Waals interaction forces tomaintain the oil/polymer blend matrix. In addition to aiding inprocessing, the mineral oil is added in amounts sufficient to providethe elastomeric composition, (e.g. the formed mattress or the cells 70described below), with the desired combination of mechanical propertiesin terms of indentation force deflection (IFD), compression set (asmeasured by ASTM D0395-16), elongation (as measured by ASTM D412-16),and droop resistance (see below). Such properties of the resultantelastomeric composition will be described in further detail below.

In certain embodiments, the amount of mineral oil in the elastomericcomposition is included at an oil/polymer weight ratio range of from1.75:1 to 3.0:1, such as from 2.5:1 to 2.9:1, such as from 2.6:1 to2.8:1, such as from 2.7 to 2.75:1.

In certain embodiments, the combination of the polymer blend and mineraloil in the elastomeric composition is present in an amount of at least85 percent by weight based on the total weight of the elastomericcomposition. Alternatively, the combination of the polymer blend andmineral oil elastomeric composition may include the polymer blend in anamount of from 85 to 100, from 88 to 100, from 91 to 100, from 94, to100, from 97 to 100, or about 98, or about 99, weight percent based onthe total weight of the elastomeric composition.

In addition, various additives could be included in the elastomericcomposition that provide various combinations of desired properties, incombination with the polymer blend and the mineral oil, to theelastomeric composition and the patient support. Such additives include,but are not limited to, colorants (such as pigments or dyes), extenders,fillers, flame retardants, plasticizers other than mineral oil,microspheres, antioxidants, UV stabilizers, flow control agents, and thelike, and combinations thereof. Such additives may be included inrelatively small amounts, such as from 0.1 to 2 weight percent, or suchas 1 percent, based on the total weight of the elastomeric composition.

As noted above, the elastomeric composition may be processed to form thepatient support. In particular, the elastomeric composition may beprocessed by extrusion, or injection molding (including multi-stageinjection molding), or other known processes, to produce the patientsupport. In other words, the aforementioned processing techniques may beused to shape the elastomeric composition to a desired geometry thusforming the resulting patient support.

As briefly referenced above, in certain embodiments, the elastomericcomposition may be used in a medical setting to form the patientsupport, such as the patient support 32 shown in FIGS. 1-5 and 7-10 .Alternatively, the elastomeric composition may be used in a non-medicalsetting to support a person.

FIG. 1 illustrates a patient support apparatus 30 including the patientsupport 32 in accordance with an exemplary embodiment of the presentdisclosure. The patient support apparatus 30 shown in FIG. 1 is ahospital bed, but alternatively may be a stretcher, cot, trolley,gurney, wheelchair, recliner, chair, table, or other suitable support ortransport apparatus. The patient support apparatus 30 may include a base34 having wheels 36 adapted to rest upon a floor surface, and a patientsupport deck 38 supported by the base 34. The illustrated embodimentshows the wheels 36 as casters configured to rotate and swivel relativeto the base 34 during transport with each of the wheels 36 disposed ator near an end of the base 34. In some embodiments, the wheels 36 may benon-steerable, steerable, non-powered, powered, or combinations thereof.For example, the patient support apparatus 30 may comprise fournon-powered, non-steerable wheels, along with one or more additionalpowered wheels. The present disclosure also contemplates that thepatient support apparatus 30 may not include wheels.

The patient support apparatus 30 may include an intermediate frame 40spaced above the base 34 with the patient support deck 38 coupled to ordisposed on the intermediate frame 40. A lift device 42 may be operablycoupled to the intermediate frame 40 and the base 34 for moving thepatient support deck 38 relative to the base 34. In the exemplaryembodiment illustrated in FIG. 1 , the lift device 42 includes a pair oflinear actuators 44, but other suitable constructions are contemplated.The illustrated embodiment also shows the patient support deck 38including articulating sections 46 configured to articulate the patientsupport 32 between various configurations. The articulating sections 46may include a fowler section 46A, a seat section 46B, a thigh section46C, a leg section 46D, and the like, operably coupled to actuators 48.For example, the actuators 48 may move the fowler section 46A between afirst position in which the patient P is supine, as illustrated in FIG.1 , and a second position in which the torso of the patient P ispositioned at an incline. For another example, a gatch maneuver may beperformed in which the positions of the thigh and/or leg sections 46C,46D are articulated to impart flexion or extension to lower extremitiesof the patient.

The patient support 32 is supported on the patient support deck 38 ofthe patient support apparatus 30. The illustrated embodiment shows thepatient support 32 as a mattress for supporting the patient P whenpositioned on the patient support apparatus 30. The patient support 32includes a crib assembly 50 to be described in detail, and in certainembodiments a cover assembly 52 within which the crib assembly 50 isdisposed.

Referring to FIG. 2 , the cover assembly 52 may include a top cover 54opposite a bottom cover assembly 56 that cooperate to define an interiorsized to receive the crib assembly 50. In certain embodiments, the coverassembly 52 may include a fastening device 57 (see also FIG. 6 ) forcoupling the top cover 54 and the bottom cover assembly 56. In oneexample, the fastening device 57 is a zipper extending about sides ofthe cover assembly 52. Other fastening devices may include snaps, clips,tethers, hook and eye connections, adhesive, and the like. In onevariant, the top cover 54 and the bottom cover assembly 56 areintegrally formed to provide the cover assembly 52 of unitary structurethat is not removable from the crib assembly 50. A watershed (not shown)may be coupled to the top cover 54 and/or the bottom cover assembly 56near the fastening device 57 to prevent ingress of fluid and othersubstances through the fastening device 57 to within the patient support32. The crib assembly 50 disposed within the cover assembly 52 may besubstantially encased within the cover assembly 52 to define the patientsupport 32. As shown in FIG. 3 , the crib assembly 50 includes a headend 33 opposite a foot end 35 separated by opposing sides 37, 39.

The patient support 32 defines a patient support surface 58 (FIG. 2 )for supporting the patient P. Absent bedding and the like, the patient Pmay be considered in direct contact with the patient support surface 58when situated on the patient support 32. Referring now to FIGS. 1 and 2, the patient support surface 58 may be considered an upper surface ofthe top cover 54 of the cover assembly 52. In a variant without thecover assembly 52, the patient support surface 58 may be considered anupper surface of the crib assembly 50. The patient support surface 58 issized to support at least a majority of the patient P. Furthermore,during movement therapy to be described, the patient support surface 58is moved relative to other structures of the patient support 32 and thepatient support apparatus 30.

Certain aspects of the crib assembly 50 will now be described withreference to FIGS. 4 and 5 . The crib assembly 50, in a most generalsense, provides the internal structure of the patient support 32 forsupporting and cushioning the patient P on the patient support surface58. The crib assembly 50 includes at least one, and in the illustratedembodiment more than one, conformable layers to resiliently deform whensupporting the weight of the patient P. FIG. 5 shows the crib assembly50 including an upper conformable layer 60 and a lower conformable layer62. The upper conformable layer 60 may include a first section 64, asecond section 65, and a third section 66 positioned along a length ofthe crib assembly 50 from the head end 33 to the foot end 35. The first,second, and third sections 64-66 may be arranged (e.g., positionedadjacent to one another) such that the upper conformable layer 60 isdisposed beneath at least a majority of the patient support surface 58.In other words, the first section 64 may be disposed near the head end33 and configured to support at least a portion of the upper body of thepatient P, the third section 66 may be disposed near the foot end 34 andpositioned to support at least a portion of the lower body of thepatient P, and the second section 65 may be disposed between the firstand third sections 64, 66 and positioned to support at least a portionof the upper and/or lower body of the patient P. More specifically, thesecond section 65 may be positioned to support the sacrum, buttocks, andthighs of the patient P, and includes features to be described thataccommodate the increased focal pressures often experienced by thepatient P in these anatomical areas.

In certain embodiments, the first, second, and/or third sections 64-66of the upper conformable layer 60 may each include a lattice 68 of cells70 to be described in greater detail. The lattices 68 of cells 70 may beintegrally formed or separately formed lattices 68 that are connectedtogether. Each lattice 68 of cells 70 may be formed of the elastomericcomposition as described above. FIG. 5 shows the first, second, andthird sections 64-66 including a head lattice, a torso lattice, and afoot lattice, respectively, with the lattices 68 of an adjacent two ofthe first, second, and third sections 64-66 positioned in aninterlocking arrangement (e.g., a hexagonal tessellation to bedescribed). In other words, the cells 70 at one end of the head lattice68 are staggered to provide a zig-zag end, and the cells 70 at acomplementary end of the torso lattice 68 are staggered to provide acomplementary zig-zag end. Likewise, the cells 70 at the other end ofthe torso lattice 68 are staggered to provide a zig-zag end, and thecells 70 at a complementary end of the foot lattice 68 are staggered toprovide a complementary zig-zag end. The complementary zig-zags arepositioned in abutting relationship to provide the interlockingarrangement such that, when assembled, the lattices 68 of the first,second, and third sections 64-66 appear integrally formed or continuous.

With continued reference to FIGS. 4 and 5 , the lattice 68 of the firstsection 64 may include a taper such that the lattice 68 appearsgenerally trapezoidal in shape when viewed in plan. The taper is shapedto accommodate a head end support 72 of the crib assembly 50. Inparticular, the head end support 72 may be generally U-shaped inconstruction with opposing legs of the head end support 72 being shapedcomplementarily to the taper of the lattice 68 of the first section 64.The first section 64 may include coupling features 74 (described furtherbelow) extending outwardly from the legs of the trapezoidal-shapedlattice 68 such that the first section 64 appears rectangular whenviewed in plan. The coupling features 74 are configured to be coupledwith an underside of the legs of the head end support 72 by a suitablejoining means, for example an adhesive. A thickness of an end of thehead end support 72 adjacent the first section 64 may be approximate athickness of the lattice 68 of the first section 64 such that, when thehead end support 72 and the first section 64 are coupled together, acontoured surface is provided. It is understood from FIGS. 4 and 5 thatthe head end support 72 may be further contoured in a manner to supportthe head of the patient P. In certain embodiments, the head end support72 may be formed from material(s) with less conformability relative tothat of the lattice 68 of the first section 64 to accommodate thedistinct considerations of supporting the head of the patient P on thepatient support 32. Of course, the head end support 72 may also beformed from the same elastomeric composition used to form the lattice68.

The second section 65 of the upper conformable layer 60 may include thelattice 68 that is generally rectangular in shape when viewed in plan.The second section 65 may include coupling features 75 a, 75 b extendingoutwardly from the rectangular-shaped lattice 68. The coupling featuresinclude upper coupling features 75 a, and lower coupling features 75 bto be described. The upper coupling features 75 a on one end of thesecond section 65 are configured to be coupled with an underside of thefirst section 64 by a suitable joining means, for example an adhesive,when the head lattice and the torso lattice are positioned in theinterlocking arrangement previously described. Likewise, upper couplingfeatures 75 a on the other end of the second section 65 are configuredto be coupled with an underside of the third section 66 with a suitablejoining means, for example an adhesive, when the torso lattice and thefoot lattice are positioned in the interlocking arrangement previouslydescribed. As best shown in FIG. 4 , a thickness of the lattice 68 ofthe second section 65 may be greater than each of the lattices 68 of thefirst and third sections 64, 66. The increased thickness of the torsolattice, among other advantages, accommodates the increased focalpressures often experienced by the patient P in the anatomical areasmentioned.

The lower conformable layer 62 may include a first section 81, a secondsection 82, and a third section 83. The first, second, and/or thirdsections 81-83 of the lower conformable layer 62 may be formed fromfoam-based material(s) and/or other suitable material(s). Thematerial(s) comprising the first, second, and/or third sections 81-83may be less conformable relative to that of the lattices 68 of thefirst, second, and/or third sections 64-66, as it is appreciated thatcushioning demands of the lower conformable layer 62 may be relativelyless than that of the upper conformable layer 60. The first section 81may be at least partially positioned beneath at least one of the headend support 72 and the first section 64 of the upper conformable layer60. In other words, an underside of the head end support 72 and/or thefirst section 64 is supported upon an upper surface of the first section81. The first section 81 may include a first portion 84 and a secondportion 85 coupled to one another at a joint 86.

As mentioned, the thickness of the lattice 68 of the second section 65may be greater than the thickness of each of the lattices 68 of thefirst and third sections 64, 66. With continued reference to FIGS. 4 and5 , an end of the first section 81 of the lower conformable layer 62 maybe positioned adjacent a corresponding end of the second section 65 ofthe upper conformable layer 60. In certain locations of the secondsection 65, there may not be a structure of the lower conformable layer62 positioned beneath the second section 65 of the upper conformablelayer 60. The second section 82 of the lower conformable layer 62 ispositioned adjacent another end of the second section 65 of the upperconformable layer 60 opposite the first section 81, as best shown inFIG. 4 . The second section 82 of the lower conformable layer 62 mayfurther be at least partially positioned beneath the third section 66 ofthe upper conformable layer 60. In other words, an underside of thethird section 66 is supported on an upper surface of the second section82.

The third section 83 of the lower conformable layer 62 may be positionedadjacent the second section 82. The third section 83 may be at leastpartially positioned beneath at least one of the second and thirdsections 65, 66 of the upper conformable layer 62. In other words, anunderside of the second section 65 and/or the third section 66 of theupper conformable layer 62 is supported upon an upper surface of thethird section 83 of the lower conformable layer 62. With continuedreference to FIGS. 4 and 5 , each of the second and third sections 82,83 of the lower conformable layer 62 may include complementarilyinclined surfaces positioned in an abutting relationship.

As mentioned, the coupling features of the second section 65 may includethe upper coupling features 75 a previously described, and lowercoupling features 75 b. The lower coupling features 75 b extendoutwardly from the rectangular-shaped lattice 68 and are spaced apartfrom the upper coupling features 75 a to define gaps therebetween. Thelower coupling features 75 b on one end of the second section 65 areconfigured to be coupled with an underside of the first section 81 by asuitable joining means, for example an adhesive, and the lower couplingfeatures 75 b on the other end of the second section 65 are configuredto be coupled with an underside of the third section 83 by a suitablejoining means, for example an adhesive. In such an arrangement, the gapsbetween the upper and lower coupling features 75 a, 75 b are sized toreceive a thickness of the first section 81 and a combined thickness ofthe second and third sections 82, 83, as best shown in FIG. 4 .

The upper conformable layer 60 and the lower conformable layer 62 areconfigured to be received in a cavity defined by a crib 90 of the cribassembly 50. In a most general sense, the crib 90 provides a frameworkof the patient support 32. In the illustrated embodiment, the crib 90may include a head end frame member 92, a foot end frame member 94, abase layer 96, and side frame members 98 with each to be described inturn. The head end frame member 92 may be generally U-shaped inconstruction with the head end frame member 92 engaging the firstsection 81 of the lower conformable layer 62 on three sides. The headend frame member 92 may include a recess 93 sized to receive an end ofthe first section 81. Further, the generally U-shaped head end framemember 92 may at least partially engage the head end support 72 on threesides. In at least some respects, the head end frame member 92 may beconsidered the head end 33 of the crib assembly 50.

The foot end frame member 94 may be coupled to the upper and lowerconformable layers 60, 62 opposite the head end frame member 92. Thefoot end frame member 94 may be coupled to an end of the third section66 opposite the second section 65. FIG. 5 shows the foot end framemember 94 being generally U-shaped in construction so that the foot endframe member 94 engages the third section 66 on three sides. Inparticular, the third section 66 of the upper conformable layer 60includes coupling features 76 extending from opposing sides of thelattice 68. The coupling features 76 are configured to be coupled withan upper surface of opposing legs of the generally U-shaped foot endframe member 94 by a suitable joining means, for example an adhesive. Inat least some respects, the foot end frame member 94 may be consideredthe foot end 35 of the patient support 32.

Flanking the upper and lower conformable layers 60, 62 are the sideframe members 98. The side frame members 98 are coupled to each of thehead end frame member 92 and the foot end frame member 94. Withconcurrent reference to FIG. 3 , the illustrated embodiment shows theside frame members 98 including inclined surfaces 100 matingly engagingcomplementary inclined surfaces 102 of each of the head end frame member92 and the foot end frame member 94. Further, the side frame members 98may be coupled to one or both of the upper and lower conformable layers60, 62. FIG. 5 shows the side frame members 98 including an upper ledge104 configured to receive the upper coupling features 75 a extendingfrom opposing sides of the second section 65 with a suitable joiningmeans, for example an adhesive.

Referring to FIG. 5 , the side frame members 98 may include slots 106 atleast partially extending transversely through the side frame members 98to define rib-like structures. The slots 106 may be provide for flexionof the side frame members 98 through relative articulation of therib-like structures secondary to the material forming the side framemembers 98. The slots 106 may further include upper and lower slotsextending inwardly from upper and lower surfaces, respectively, of theside frame members 98.

The side frame members 98 coupled to each of the head end frame member92 and the foot end frame member 94 may be considered to define aperimeter of the crib 90. The aforementioned cavity within which theupper and lower conformable layers 60, 62 are received is furtherdefined by the base layer 96. Referring again to FIG. 5 , the base layer96 may be a planar structure to which each of the head end frame member92, the foot end frame member 94, and the side frame members 98 arecoupled. The base layer 96 is positioned beneath the lower conformablelayer 62 such that an upper surface the base layer 96 may support thelower conformable layer 62. The base layer 96 may include at least onechannel 108 sized to receive a first conduit assembly 110. The firstconduit assembly 110 is configured to be in communication with a fluidsource (not shown) to at least partially define a fluid flow path andcirculate fluid from the fluid source, for example, air or conditionedfluid, through the fluid flow path to supply heat, remove heat, supplymoisture, remove moisture, or the like, from the patient support surface58. In other words, the first conduit assembly 110 circulating fluid maybe utilized to control the conditions at or near an interface betweenthe top cover 54 and the skin of the patient, to control the temperatureand/or humidity at the interface. The base layer 96 may also defineapertures 112 to accommodate structures of a patient turning system 200to be described in greater detail. In certain embodiments, the cribassembly 50 includes a fire barrier layer 114 (see FIG. 2 ). Exemplaryfire barrier layers suitable for the present application may be providedunder the tradename NoMex (DuPont Company, Wilmington, Del.), and underthe tradename Integrity 30 (Ventrex Inc., Ashburn, Va.).

The patient support 32 may include a spacer layer 116 coveringsubstantially an entirety of an upper surface of the crib assembly 50.More particularly, the spacer layer 116 covers the head end support 72and the upper conformable layer 60. As best shown in FIG. 5 , the spacerlayer 116 may include coupling features 118 with the coupling features118 at one end sized to receive the crib assembly 50, and moreparticularly the head end frame member 92. The coupling features 118 atthe opposing end are configured to be coupled to the foot end framemember 94. The coupling features may be gusset-like features, such aselastic gussets conventionally provided on fitted sheets.

As previously mentioned, the top cover 54 is coupled to the bottom coverassembly 56, for example, with the fastening device 57. Components andfeatures of the bottom cover assembly 56 will now be described withreference to FIG. 6 . The bottom cover assembly 56 includes a carriersheet 120. An upper surface of the carrier sheet 120 may be consideredthe structure in direct contact with an underside of the base layer 96when the patient support 32 is assembled. At least one coupler 122 maybe coupled to and extend from the upper surface of the carrier sheet120. The couplers 122 are configured to secure a second conduit assembly124 of the patient turning system 200 to be described. An underside ofthe base layer 96 may include additional channels (not shown) sized toreceive the second conduit assembly 124 such that the underside of thebase layer 96 and the upper surface of the carrier sheet 120 are indirect flat-on-flat contact. The carrier sheet 120 may include a baseportion 126 and opposing sides 128 extending upwardly from the baseportion 126. The fastening device 57 may be coupled to an upper edge ofthe opposing sides 128.

A bottom cover 130 may be coupled to the carrier sheet 120 to define abottom of the patient support 32. In other words, an underside of thebottom cover 130 may be considered the surface in direct contact withthe patient support deck 38 of the patient support apparatus 30 (seeFIG. 1 ). The bottom cover 130 may include a head end section 132, amiddle section 134, and a foot end section 136. The head end section132, the middle section 134, and the foot end section 136 may beintegrally formed or discrete components coupled to one another. Thehead end, middle, and foot end sections 132-136 collectively define acavity sized to receive the carrier sheet 120, at least one patientturning device 202 of the patient turning system 200, and at least aportion of the crib assembly 50 previously described. In particular, anupstanding sidewall of each of the head end section 132 and the foot endsection 136 may be arcuate and contoured to the head end frame member 92and the foot end frame member 94, respectively, of the crib assembly 50.In the illustrated embodiment of FIG. 6 , one or more handles 138 arecoupled to head end, middle, and/or foot end sections 132-136 to assistcaregivers with manipulating the patient support 32 when the patientsupport 32 is disposed on the patient support deck 38.

The foot end section 136 defines a recess 140 sized to receive a portconnector 142. In short, the port connector 142 includes ports (notshown) configured to be in fluid communication with the aforementionedfluid source, and further configured to be in fluid communication withthe first conduit assembly 110 and the second conduit assembly 124. Therecess 140 of the foot end section 136 may be substantially aligned witha void between the gusset-like coupling features 118 coupled to the footend frame member 94. The recess 140 of the foot end section 136 may alsobe substantially aligned with a complementary recess 141 defined withinthe foot end frame member 92, as shown in FIG. 5 . The port connector142 is positioned within the recesses 140, 141 so as to be accessible bycaregivers positioned near the foot end 35 of the patient support 32.

The middle section 134 of the bottom cover 130 includes a base portion144 and opposing sides 146 extending upwardly from the base portion 144.The fastening device 57 may be coupled to an upper edge of the opposingsides 146 (with or without also being coupled to the upper edge of theopposing sides 128 of the carrier sheet 120). With the carrier sheet 120received within the middle section 134 of the bottom cover 130, the baseportion 126 of the carrier sheet 120 is adjacent the base portion 144 ofthe bottom cover 130 (other than the presence of the patient turningdevices 202), and the opposing sides 128 of the carrier sheet 120 areadjacent the opposing sides 146 of the bottom cover 130. The baseportion 144 and/or opposing sides 146 of the bottom cover 130 may definean augmenting feature 148. In short, because the patient turning devices202 are positioned external to the crib assembly 50 yet within thebottom cover assembly 56, the augmenting features 148 accommodate theexpansion of the patient turning devices 202 and prevent “hammocking” ofthe patient support surface 58 during the movement therapy (i.e.,localized alteration or stretching of the patient support surface 58 toa generally concave or arcuate contour that results in localizedpressure points). For example, the augmenting features 148 may includethe opposing sides 146 of the bottom cover 130 to be at least partiallyformed from Neoprene and/or other suitably elastic material(s), such asthe elastomeric composition.

With continued reference to FIG. 6 and concurrent reference to FIG. 4 ,the patient support 32 includes at least one of the patient turningdevices 202 for moving the patient support surface 58, for example,during the movement therapy. The patient turning devices 202 arepositioned between the carrier sheet 120 and the bottom cover 130. Moreparticularly, the patient turning devices 202 are coupled to anunderside of the carrier sheet 120 and may not be coupled to the bottomcover 130. The patient turning devices 202 include at least one inletport 204, 206 configured to be arranged in fluid communication with thesecond conduit assembly 124, the ports (not shown) of the port connector142, and the fluid source. The carrier sheet 120 includes at least oneaperture 154 sized and positioned such that, when the patient turningdevices 202 are coupled to the carrier sheet 120, the inlet ports 204,206 extend through the apertures 154. In manners to be described, atleast one of the patient turning devices 202 is configured to beselectively inflated and deflated in order to move at least a portion ofthe patient support surface 58 away from or towards the patient supportdeck 38, respectively.

Referring to FIG. 7 , the crib assembly 50 is shown, including eachlattice 68 of cells 70. In other versions, the crib assembly 50 maycomprise one integrally formed lattice of cells, instead of separatelyformed lattices 68 that are connected together. In the embodiment shown,as described above, three separate lattices 68 are provided (see FIG. 5) including the head lattice, the torso lattice, and the foot lattice.One objective of forming the lattices 68 with the elastomericcomposition is to minimize the occurrence of pressure sores/ulcers byproviding uniform pressure support for a range of patient weights. It isto be appreciated the uniform pressure support is established by thecombination of the elastomeric composition and the particular geometryof the lattices 68 formed therefrom.

Referring to FIGS. 8-10 , each lattice 68 of cells 70 is notparticularly limited in size or configuration. For example, the lattice68 itself may have a periphery that is configured in any shape includingrectangular, trapezoidal, square, or in any other shape. Moreover, thelattice 68 may be of any length, width, and depth. The cells 70themselves are also not particularly limited in size, shape, orconfiguration. The cells 70 may be shaped as a triangle, square,rectangle, pentagon, hexagon, etc. In FIG. 10 , the cell 70 is shaped asa hexagon, referred to as hexagonal cell 170. In another embodiment (notshown), the cell 70 is shaped as a triangle, referred to as a triangularcell. The cells 70 may be all of the same shape and size or may be ofdiffering shapes and/or sizes. For example, some of the cells 70 may behexagonal while others may have four sides. Further, the cells 70 of thelattice 68 may fit together laterally and/or longitudinally in acomplementary pattern or may be offset from one another.

In some embodiments, the cells 70 are disposed in the crib 90 so that noother cells are disposed between the cells 70 and the bottom of the crib90 or between the cells and the top cover 54. In one words, in someembodiments, the lattices 68 are arranged in the crib 90 so that nolattice is stacked on top of another lattice, i.e., only a single layerof cells 70 is present within the cover assembly 52, between the top andbottom layers of the cover. In some embodiments, the lattices 68 arearranged so that at least one lattice (e.g., the torso lattice) has noother lattices stacked above or below it, but adjacent lattices, such asthe head and/or foot lattices, may have other lattices stacked thereonor thereunder. It should be appreciated, however, that other layers,such as the coupling features 74, 75 a, 75 b, may be present between thecells 70 and the bottom of the crib 90 or between the cells 70 and thetop cover 54.

Referring back to FIG. 10 , each of the cells 70 includes a base 156 andextends to a top 158 opposite the base 156. Each of the cells 70 hasthree or more walls 164, shown in FIG. 10 as six walls 164, having athickness and extending from the base 156 to the top 158 to form acolumn 162 having a height H and width W that defines an interior volume(V) within a perimeter of the three or more walls 164. Accordingly, thecells 70 with six walls 164 in FIG. 10 may further be defined ashexagonal cells 170

The walls 164 may be singular or may include two individual walls spacedlaterally from one another thereby defining a void therebetween. Thevoid may remain empty or may be filled with any filler in the art. Incertain embodiments, one or more of the walls 164 of the lattice ofcells 70, 170 are further defined as buckling elements, which compressand then buckle under pressure, i.e., move laterally, so as to balancepressure exerted upwards on the patient. The buckling elements offerlittle resistance to deformation thereby reducing pressure on thepatient.

The elastomeric composition (as formed from the polymer blend of thefirst and second SEEPS copolymers, mineral oil and additives asdescribed above) may be processed by extrusion, or injection molding(see the Examples describing one injection molding method), or otherknown processes, to produce the patient support 32 including the cells70, 170 of each lattice 68, as illustrated in FIGS. 1-5 and 7-10 , or tootherwise form a support for a person.

Referring now to the physical properties of the elastomeric composition(as formed from the polymer blend of the first and second SEEPScopolymers, mineral oil and additives as described above), the cells 70,170 used in the lattices 68 of the patient support 32 can be formed witha desired indentation force deflection (IFD). The IFD test is one ofmultiple test methods that are defined in ASTM D3574. Within ASTM D3574,the indentation force deflection procedure is Method B1 which measuresthe force (in pounds) required to indent an eight inch diameter steelplate (called an indentor foot) into a sample (here the formedelastomeric composition (such as the cells 70, 170), formed from theelastic compositions described above), to a stated percentage of thetest sample's initial height which is commonly four inches. The IFD ofthe elastomeric composition is typically between 15 and 60 pounds offorce as measured in accordance with ASTM D3574 B1, depending upon thepart geometry wherein the part is compressed to approximately 50% of itsthickness (e.g. to about 2 inches). In the cells 70, 170 particularlydescribed in FIGS. 1-10 above (and including the elastomericcomposition) for use in the patient support apparatus 30, the IFD of thecells 70, 170 is measured between 15 and 60 pounds of force, such asbetween 20 and 30 pounds of force, to compress the cell 70, 170 to about50% of its thickness.

Still further, the elastomeric composition (as formed from the polymerblend of the first and second SEEPS copolymers, mineral oil andadditives as described above) also provides acceptable mechanicalproperties in terms of average droop resistance, compression set andelongation characteristic (both prior to and after heat aging designedto simulate use), and thus further confirms its appropriateness for usein the cells 70, 170 used in the lattices 68 of the patient support 32.In fact, the elastomeric composition as described above provides similarcompression set and elongation properties (measured in accordance withASTM standards D0395-16 and D412-16, respectively) to elastomericcompositions in which Kraton® 1830 (a polymer having a hydrogenatedmidblock of styrene-ethylene/butylene-styrene (SEBS), available fromKraton Corporation) replaces the polymer blend described above at thesame mineral oil/polymer ratio of 2.7-2.75:1.

EXAMPLES Example 1: Preparation of Elastomeric Composition MoldedPlaques

Elastomeric Compositions for evaluation in Examples 2 and 3 below wereprepared under the following procedure.

First, formulation for forming the elastomeric compositions evaluated inExamples 2 and 3 are provided in Table 1:

TABLE 1 Elastomeric Compositions for Evaluation Component Weight PercentComponent Description Weight of Total 1 Polymer Blend¹ 10 g 26.4% 2Mineral Oil 27.5 g 72.56%  3 Stabilizers² 0.3 g  0.8% 4 Colorant³ 0.1 g0.26% Total 37.9 g  100% ¹Blend of First SEEPS copolymer (Mw (weightaverage) about 308,000, styrenic content about 30%) and Second SEEPScopolymer (Mw (weight average) of about 150,000, styrenic content about32%). ²Evernox 1010 (antioxidant) and Everfos 168 (phosphite processingaid), stabilizers commercially available from Everspring Chemical Co.,Ltd of Taichung, Taiwan. ³Sunfast blue pigment available from SunChemical Corporation of Parsippany, New Jersey.

In Table 1, the weight ratio of the First SEEPS copolymer to the secondSEEPS copolymer was varied between 100:0 and 10:90 (i.e., 100% of theFirst SEEPS copolymer to a blend of 10% by weight of the first SEEPScopolymer and 90% of the second SEEPS copolymer).

To form the elastomeric composition, components 1, 2 and 4 were firstdry blended until uniformly distributed into a dry mixture. Component 2was added to the dry mixture and mixed to form the elastomericcomposition having a polymer/polymer blend to mineral oil weight ratioof 2.75:1.

The elastomeric composition was then introduced into a multi-stageinjection molding machine including multiple temperature zones set atvarying temperatures (and typically increasing temperatures), with themolded part ejected at the nozzle end after traversing the multipletemperature zones. The elastomeric composition was then molded intomolded test plaques, which were removed from the Toshiba machine, withthe plaques evaluated for packout, clarity, bubbles, waviness,fractures, snake skin and the like. Minor adjustments to temperatureprofiles, screw speed, or polymer/polymer blend to mineral oil weightratio, as needed, were performed as needed for each representativeelastomeric composition to ensure that the molded test plaques hadsimilar properties in terms of packout, clarity, bubbles, waviness,fractures, snake skin and the like. The molded test plaques were thenavailable for use in the evaluations described in Examples 2 and 3below.

Example 2: Average Droop Resistance Testing for Various Blends of theFirst and Second SEEPS Copolymers

Molded test plaques of the elastomeric composition were prepared inaccordance with the method described in Example 1, in which the weightratio of the first and second SEEPS copolymer was varied between 100:0and 10:90.

Sample test plaques of about 5 inches wide by 5.75 inches long (about14.6 cm by 12.7 cm) having a thickness of about ⅛ inch (about 0.3 cm)were then die cut from the molded test plaques. These sample testplaques were then conditioned in an undeflected and undistorted state atambient temperature and humidity for at least 12 hours before testing.Initial IFD measurements for the test plaques were measured at 50%compression in accordance with ASTM D3574 B1.

A first end of each of the plaques was then coupled to a verticalmember, with the opposite open second end extending horizontally awayfrom the vertical member. One half of the test plaques for eachrepresentative sample were then subjected to a load of 0.17 pounds persquare inch (about 1.17 kilopascals) directed downward on the top of theplaque at a position corresponding to the open second end, while theremaining test plaques received no load. The test plaques were placed inan oven at about 60 (+/−2) degrees Celsius for approximately 36 hours.

The samples were removed from the oven and maintained in ambientconditions and ambient humidity for 12 hours. At this point, theunloaded samples were retested to confirm that the IFD measurementremained essentially constant to the IFD measurements performed beforeheat aging. In addition, the loaded test plaques were measured for droopresistance (i.e., deflection downward measured in millimeters relativeto horizontal) relative to horizontal at the open second end. The droopfor each representative loaded plaque was measured. The average droopresults of multiple test plaques measured for each representativepolymer blend, illustrated in FIG. 11 , confirms generally that sampleshaving higher amounts of the first SEEPS copolymer relative to thesecond SEEPS copolymer exhibited the lowest droop. Further, FIG. 11 alsosurprisingly and unexpectedly confirms that the least droop occurred inthe sample test plaques formed from an elastomeric composition having85% by weight of the first SEEPS copolymer and 15% by weight of thesecond SEEPS copolymer.

Example 3: Compression Set and Elongation Testing of Samples at 80/20 or90/10 Weight Ratio of the First SEEPS Copolymer to the Second SEEPSCopolymer after Heat Aging

Additional evaluations of test plaque samples formed in Example 1 of thehigher weight ratio samples (samples at 80:20 and 90:10 weight ratios)of the first SEEPS copolymer to second SEEPS copolymer were performed todetermine compression set and percent elongation after heat aging. Forcomparison, a reference test material molded plaque was also formed inaccordance with the procedure of Example 1 above and evaluated with thetest plaque samples described above. The reference test materialutilized Kraton® 1830 (a styrene-ethylene/butylene-styrene (SEBS)copolymer manufactured by Kraton Corporation) instead of the polymerblend of the first and second SEEPS copolymers in the elastomericcompositions.

With respect to compression set testing and percent elongation, testplaque samples were evaluated for percent decrease in size in accordancewith ASTM test procedure D0395-16 (Standard Test Methods for RubberProperty—Compression Set) and D412-16 (Standard Test Methods forVulcanized Rubber and Thermoplastic Elastomers—Tension). The results ofthis testing for multiple samples of each polymer blend or polymer,after heat aging at 72 hours, 144 hours, and 216 hours, respectively,are provided in Tables 2 and 3:

TABLE 2 ASTM test procedure D0395-16 - Measured as Percent Compressionof Samples Test Plaque Description (Polymer Blend Weight Ratio of FirstSEEPS to Second SEEPS copolymer 72 144 216 or Polymer) Hours Hours Hours80:20 25% 28% 33% 90:10 24% 27% 32% 100% Kraton ® 1830 22% 25% 31%

TABLE 3 ASTM test procedure D412-16- Measured as Percent Elongation ofSamples Test Plaque Description (Polymer Blend Weight Ratio of FirstSEEPS to Second SEEPS copolymer 72 144 216 or Polymer) Hours Hours Hours80:20 4.8% 5.5% 5.0% 90:10 2.6% 4.0% 4.4% 100% Kraton ® 1830 5.9% 6.7%6.9%

Tables 2 and 3 confirm that the test sample plaques formed fromelastomeric compositions having weight ratios of 80:20 and 90:10 of thefirst and second SEEPS copolymer generally performed comparably orbetter to test plaques formed from elastomeric compositions utilizing100% Kraton® 1830 in place of the first and second SEEPS copolymer inthe elastomeric composition.

Several embodiments have been discussed in the foregoing description.However, the embodiments discussed herein are not intended to beexhaustive or limit the invention to any particular form. Theterminology which has been used is intended to be in the nature of wordsof description rather than of limitation. Many modifications andvariations are possible in light of the above teachings and theinvention may be practiced otherwise than as specifically described.

What is claimed is:
 1. A patient support for supporting a patient, thepatient support comprising: a crib assembly comprising a lattice ofcells formed from an elastomeric composition, with said cells directlyabutting adjacent cells, said elastomeric composition comprising apolymer blend, said polymer blend consisting essentially of: 85% byweight of a first SEEPS copolymer having a weight average molecularweight of weight of at least 200,000 g/mol; and 15% by weight of asecond SEEPS copolymer having a weight average molecular weight rangingfrom 125,000 to 175,000 g/mol, wherein the sum of said first SEEPScopolymer and said second SEEPS copolymer in said polymer blend is 100weight percent; and wherein said elastomeric composition furthercomprises mineral oil, and wherein the weight ratio of mineral oil topolymer blend in said elastomeric composition ranges from 2.7:1 to2.75:1.
 2. The patient support of claim 1, wherein said first SEEPScopolymer has a weight average molecular weight of about 308,000 g/moland said second SEEPS copolymer has a weight average molecular weight ofabout 150,000 g/mol.
 3. The patient support of claim 2, wherein thestyrene content of said first SEEPS copolymer is about 30 wt. % andwherein the styrene content of said second SEEPS copolymer is about 32wt. %.
 4. The patient support of claim 3, wherein said elastomericcomposition has an indention force deflection of from 15 to 60 pounds asmeasured in accordance with ASTM D3574 B 1 when said elastomericcomposition is compressed to about 50% of its initial thickness.
 5. Thepatient support of claim 3, wherein each of said lattice of cells has anindention force deflection of from 20 to 30 pounds as measured inaccordance with ASTM D3574 B1 when said cell is compressed to about 50%of its initial thickness.